1. Field of the Invention
The present invention relates to a method for controlling network access in a directional communication network, and an apparatus using the same. More specifically, the present invention relates to a method for controlling network access in a case when two moving objects move through the same service duration between radio units (RUs) in a directional communication network.
2. Description of Related Art
A directional communication network for railway communication is provided with radio units (RUs) such as a remote radio head (RRH) along tracks, and terminal equipment (TE) in a means for transportation connects communication between a digital unit in a base station and a user terminal in the means for transportation through the RU. Such a directional communication network has the following merits compared to a non-directional communication network. In the directional communication network, a beam directs precisely in a railway direction, interference with another system that uses the same frequency bandwidth can be reduced, much wider coverage can be allowed with a power limitation, and much higher system throughput can be supported by freely using an unregistered frequency bandwidth such as a millimeter wave (mm wave).
In such a directional communication network, the terminal equipment (TE) in the moving object has relatively high mobility and thus a radio unit (RU) of the terminal equipment (TE) in the moving object is frequently changed, thereby causing frequent occurrence of handover. In this case, a network random access success rate and a network random access delay become core indicators for evaluating system performance. In most cases, moving objects are rarely distributed on railways, so TEs installed in the moving objects can use the entire system resources. However, when two moving objects cross each other, radio resource management (RRM) and scheduling may be needed because radio resources such as a frequency and time are allocated to two TEs. In this case, the network random access delay may be increased in order to process the RRM and the scheduling.